The present invention herein resides generally in the art of motor assemblies. In particular, the present invention relates to bypass motor fan assemblies which employ a vent cover. Specifically, the present invention is directed to a brush clamp clip that functions to hold a motor brush in place while also retaining the vent cover to the motor assembly.
Bypass motor fan assemblies are used in various types of industrial and commercial applications. One of their more common applications is for vacuum devices wherein a fan is rotated by a motor shaft to draw working air into a housing and wherein the air is exhausted radially out the housing. This working air does not come in contact with the motor windings and as such is normally dirt-free and moisture-free. In order for the motor assembly to operate properly the motor is cooled by at least one cooling fan that is driven by the same motor shaft.
In order to ensure the safe operation of the motor cooling fan, a vent cover is disposed over the cooling fan and attached to the motor assembly to prevent foreign objects from interfering with the rotation of the fan and to keep other foreign matter away from the motor assembly. In the past, these vent covers were secured to a motor holding bracket by a friction fit. For those vent covers which are secured only by frictional forces it has been found that the vent cover is easily dislodged and accordingly poses a safety and reliability problem.
One solution for retaining the vent cover to the motor assembly is shown in FIGS. 1-7. As can be seen in the drawings, a bypass motor fan assembly is designated generally by the numeral 20. The assembly 20 includes a fan housing 22 which is secured to a fan end bracket 24. Secured to an opposite side of the fan end bracket 24 is a motor assembly 26 which provides a rotating shaft which rotates a fan (not shown) that is enclosed by the fan housing 22. The motor assembly 26 includes a motor bracket 28 which carries at least a pair of motor brushes 30 which are in contact with the commutator of the motor assembly 26. As used herein, reference to motor brush 30, may be to just a brush or to a sleeve-type housing which carries and spring biases the brush. A cooling fan (not shown) is rotated by the motor shaft and is carried at the end of the shaft opposite the working air fan. The brush 30 is secured to the motor bracket 28 by a brush clamp 40. As best seen in FIGS. 2-4, the brush clamp 40 is an inverted U-shaped metallic piece which has a top member 42 which may be provided with a detent 44 that retains the motor brush 30 in place. Downwardly extending from the edges of the top member 42 are a pair of sides 46 from which perpendicularly extend a flange 48. Flange holes 50 extend through the flanges 48 to allow for receipt of fasteners 52 which secure the brush clamp 40 to the motor bracket and which allow for retention of the motor brush 30.
After the brush clamp 40 is secured to the motor bracket to retain the motor brush 30, the vent cover 32 is positioned over the motor bracket and axially positioned in a proper orientation to permit a friction fit between the vent cover 32 and the motor bracket 28. A prior art clip, designated generally by the numeral 60, as best seen on the left side of FIG. 1 and in FIGS. 5-7, is installed radially to secure the vent cover 32 to the brush clamp 40 and the motor bracket 28.
The clip 60 includes a leg portion 62 from which substantially perpendicularly extends a foot 64. Further extending in the same direction as the foot 64 are a pair of tines 66 which form a slot 68. Extending substantially perpendicularly from the leg portion 62 is a shoulder portion 70. Further extending from the shoulder portion is a bend 72 which has a downwardly extending tab 74. The tab 74 preferably extends in a direction toward the leg portion 62.
It will be appreciated that the tines 66 are inserted between the top member 42 and the top surface of the motor brush 30. The slot 68 receives the detent 44 such that the clip 60 may be fully inserted into the brush clamp 40. As the clip 60 is radially directed between the brush clamp 40 and the brush 30, the bend portion 72 contacts a portion of the vent cover and is primarily deflected or pivoted at the shoulder portion 70 until a clearance is obtained and the shoulder portion 70 returns to its original position. The tab 74 functions to hold onto a corresponding surface of the vent cover and as such the clip cannot be radially withdrawn until the shoulder portion 70 is pivoted upwardly, and the tab 74 no longer contacts the vent cover 32.
Although the prior art clip 60 is effective, several drawbacks have come to light. It has been found that the clip 60 retains the vent cover in such a manner that makes it difficult to service or repair the cooling fan or any component of the motor assembly. This is primarily attributable to the fact that the bend portion 72 must be pivoted upwardly at the shoulder portion 70 while simultaneously applying an outward radial force. Such a procedure is quite difficult and often results in breakage of the clip on the vent cover at the shoulder portion of the clip. It has also been found that manually installing the clip 60 in a manufacturing environment leads to concerns about repetitive motion stresses to the worker who is installing the clips. It has also been found that the clips 60 are sometimes difficult to align and, as such, the vent cover may not be properly secured to the motor bracket as required for safe operation of the attached motor fan assembly.
Therefore, based upon the foregoing, there is a need in the art for a more reliable way to secure a vent cover to a motor assembly and to provide a clip or retention device that is more reliable in operation and in installation.
Therefore, it is a first aspect of the present invention to provide a bypass motor fan assembly having a vent cover retention clip, comprising a motor assembly having a motor bracket which carries at least a pair of motor brushes; a vent cover coupled to said motor assembly; and an integral clip secured to said motor bracket for slidably retaining said motor brushes and for retaining said vent cover to said motor bracket.
Another aspect of the present invention, which shall become apparent as the detailed description proceeds, is an integral brush clamp and vent cover retention clip for retaining a vent cover to a motor assembly, comprising a brush clamp attachable to the motor assembly; and a deflectable finger integrally extending from said brush clamp, said deflectable finger securable to the vent cover, wherein said deflectable finger is pivotable with respect to said brush clamp.
Other aspects of the present invention are attained by a method for assembling a motor assembly having a vent cover, comprising assembling a motor assembly having a motor bracket; retaining at least one motor brush to said motor bracket with an integral brush clamp and vent cover retention clip; and pressing a vent cover on to said motor bracket after said clamping step such that said clip retains said vent cover.